Converter for enhanced efficiency power conversion
Methods and systems for transforming electric power between two or more portals. Any or all portals can he DC, single phase AC, or multi-phase AC. Conversion is accomplished by a plurality of bi-directional conducting and blocking semiconductor switches which alternately connect an inductor and parallel capacitor between said portals, such that energy is transferred into the inductor from one or more input portals and/or phases, then the energy is transferred out of the inductor to one or more output portals and/or phases, with said parallel capacitor facilitating “soft” turn-off, and with any excess inductor energy being returned back to the input. Soft turn-on and reverse recovery is also facilitated. Said hi-directional switches allow for two power transfers per inductor/capacitor cycle, thereby maximizing inductor/capacitor utilization as well as providing for optimum converter operation with high input/output voltage ratios. Control means coordinate the switches to accomplish the desired power transfers.
1. A converter for enhanced efficiency power conversion, comprising:
first and second switch arrays, each comprising at least two bidirectional switching devices;
an inductor connected in parallel to each of the switch arrays;
a capacitor connected in parallel to each of the switch arrays;
wherein a first one of said switch arrays is operatively connected to a power input, and is operated to drive power, into the combination of said inductor and said capacitor, with a non-sinusoidal waveform;
and wherein a second one of said switch arrays is operated to deliver power to a power output;
and wherein said switch arrays are each operated to perform two separate power transfers during each full cycle of current through said inductor;
and wherein there is no direct connection between said inductor and said power input.
2. The converter of claim 1 , wherein said switch arrays include full bridge arrays.
3. The converter of claim 1 , wherein said switch arrays are symmetrically connected to said energy-transfer reactance.
4. The converter of claim 1 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays.
5. The converter of claim 1 , wherein said power input is shunted by a capacitor which provides a low-impedance voltage thereat.
6. The converter of claim 1 , wherein said power output is shunted by a capacitor which provides a low-impedance voltage sink thereat.
7. The converter of claim 1 , wherein said inductor is implemented by a transformer.
8. A converter, comprising:
an energy transfer reactance comprising at least one inductor;
a plurality of input switch arrays each connected in parallel to the inductor, each such array configured to drive AC current, with no average DC current, through said reactance;
a plurality of output switch arrays each connected in parallel to the inductor, each connected to extract energy from said reactance;
said arrays having no more than two switches driving or extracting energy from said reactance at any given time;
wherein said input arrays drive said reactance with a non-sinusoidal voltage waveform;
and wherein said energy transfer reactance has no connection to any power input nor power output terminals, except through ones of said switch arrays;
and wherein said arrays perform one complete power transfer during each interval of current flow through said energy transfer reactance in each direction.
9. The converter of claim 8 , wherein said switch arrays include full bridge arrays.
10. The converter of claim 8 , wherein said switch arrays each selectably connect said reactance to a low-impedance voltage source/sink.
11. The converter of claim 8 , wherein said inductor is implemented as a transformer.
12. The converter of claim 8 , wherein said inductance is paralleled by a capacitor.